{"id":"GHSA-534c-hcr7-67jg","aliases":[],"url":"https://o3.security/vulnerability/GHSA-534c-hcr7-67jg","summary":"Kimai has an XXE Leading to Local File Read","details":"### Summary\nKimai uses [PHPSpreadsheet](https://github.com/PHPOffice/PhpSpreadsheet) for importing and exporting invoices. Recently, a [CVE](https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-ghg6-32f9-2jp7) was identified in PHPSpreadsheet, which could lead to an XXE vulnerability.\n\n\n### Details\n\nExploitation requires an Administrator account, allowing the upload of an `XLSX` template containing the payload. The vulnerability is triggered by the following code snippet:\n\n```php\n// https://github.com/kimai/kimai/blob/b1903ba18359be16dd32ea9c40377c486498f082/src/Invoice/Renderer/AbstractSpreadsheetRenderer.php#L41\npublic function render(InvoiceDocument $document, InvoiceModel $model): Response\n{\n    $spreadsheet = IOFactory::load($document->getFilename());\n    $worksheet = $spreadsheet->getActiveSheet();\n    $entries = $model->getCalculator()->getEntries();\n    $sheetReplacer = $model->toArray();\n    $invoiceItemCount = \\count($entries);\n    if ($invoiceItemCount > 1) {\n        $this->addTemplateRows($worksheet, $invoiceItemCount);\n    }\n}\n```\n\nThe `IOFactory::load` function utilizes `simplexml_load_string`, which has previously been demonstrated to be vulnerable to XXE attacks.\n\nWhile this is not directly an XXE in Kimai, it does however impact the latest stable version.\n\n \n### PoC\n\nBy uploading a malicious `XLSX` template, the payload will be triggered every time an invoice is generated.\n\n```xml\n<?xml version=\"1.0\" encoding='UTF-7' standalone=\"yes\"?>\n+ADw-!DOCTYPE foo [ <!ENTITY % xxe SYSTEM \"php://filter/.......\" > %xxe;]>.....\n```\n\nFor a better a visibility, I will upload both a:\n- Malicious template sample for testing \n- An exported invoice, showing the contents of target file during the export. \n\n### Impact\nLocal File Read / RCE in edge cases where `phar://` can be utilized with [gadget chains](https://github.com/ambionics/phpggc) . \n\n\n[export.xlsx](https://github.com/user-attachments/files/16803913/export.xlsx)\n[sample_template.xlsx](https://github.com/user-attachments/files/16803916/sample_template.xlsx)\n","published":"2024-09-17T18:36:50Z","modified":"2024-12-05T05:27:02.542414Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"kimai/kimai","fixedVersion":"2.21.0"}],"fix":{"url":"https://github.com/kimai/kimai/commit/3204dcb03e1003dba90178667a4667ce3edb87b5","label":"kimai/kimai@3204dcb"},"references":[{"type":"WEB","url":"https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-ghg6-32f9-2jp7"},{"type":"WEB","url":"https://github.com/kimai/kimai/security/advisories/GHSA-534c-hcr7-67jg"},{"type":"WEB","url":"https://github.com/kimai/kimai/commit/3204dcb03e1003dba90178667a4667ce3edb87b5"},{"type":"PACKAGE","url":"https://github.com/kimai/kimai"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2024-12-05T05:27:02.542414Z"}}